The SRM Firmware is the firmware for Alpha systems. When powering on the CPU, it starts the code from the SRM Firmware EPROM chip, running the hardware SRM console, which is the primary human interface to the system. It allows to manage basic system hardware, troubleshoot and configure the hardware, and boot operating systems. Basically it is reading commands from a keyboard, and displaying output to a terminal.
The acronym SRM is derived from the phrase Alpha System Reference Manual, the publication detailing the Alpha architecture and which specified various features of the SRM firmware.
The SRM console was initially designed to boot DEC's OSF/1 AXP (later called Digital UNIX and finally Tru64 UNIX) and OpenVMS operating systems, although various other operating systems (such as Linux Red Hat, NetBSD, OpenBSD, and FreeBSD, for example) were also written to boot from the SRM console.
The third proprietary operating system published for the Alpha architecture – Microsoft Windows NT – did not boot from SRM; instead, Windows booted from the Advanced RISC Computing (ARC) boot firmware. (ARC is also known as AlphaBIOS.)
The hardware SRM console is capable of displaying on either a graphical adapter (such as a VGA card) or, if no graphical console and/or local keyboard is detected, on a serial connection to a VT100-compatible terminal. In this way the SRM console is similar to the Open Firmware used in SPARC and Apple PowerMac computers, for example.
Several commands are available by typing them at the prompt, and a list of possible commands is available by entering the command
help at the prompt. Various system variables for establishing automatic boot settings, parameter strings to be passed to an operating system and the like may also be set from the SRM prompt. The SRM firmware contains drivers for booting from boot media including SCSI hard disks and CD-ROM drives attached to a supported SCSI adapter, various IDE ATA and ATAPI devices, and network booting via MOP, BOOTP or DHCP is possible with supported network adapters.
The SRM firmware also contains the OpenVMS and Tru64 UNIX PALcode.
SRM and the ES40 Emulator
The ES40 Emulator runs the original ES40 SRM Firmware. How to get it is described here. The ES40 Emulator patches the firmware at runtime to optimize it for emulation purposes. Of course it is no longer kept in a chip but in a file.
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